The invention concerns a mechanism with an ingoing and an outgoing shaft for transforming a rotation with constant angular velocity to a rotation with periodically varying angular velocity. In the prior art is known a mechanism of this sort with an ingoing shaft, a universal joint no. one with pivots, a ringshaped middle part, which is firmly combined with the pivot, a universal joint no. two with pivots and an outgoing shaft, the ringshaped middle part has only one pivot for the first and the second universal joint, and so there is not achieved a summation of the angular velocity amplitudes which can arise in the single joints, when they are adjusted to an angular deflection, by the ringshaped middlepart being tilted round a diameter, which is at right angles to the ingoing and the outgoing shaft, this mechanism achieves a periodically varying angular velocity by the pivots of the second universal joint having an angle between them, differing from 90.degree..
Another mechanism is known in the prior art having coaxial ingoing and outgoing shafts, two universal joints connected in series, wherein the output of one universal joint is an adjustable middle part which is the input of the other universal joint, wherein the one universal joint is connected with the ingoing shaft via a fixed component in form of an arch with pivots or bearings for pivots on its extremities as the ingoing shaft goes through the outgoing shaft which is hollow and carries the ingoing shaft whereby both the ingoing and the outgoing shaft go through the swingable adjustable middle part, which means that the swingable adjustment by the middle part is substantially limited because both the ingoing and the outgoing shaft go through said middle part.
Another mechanism for transforming a rotation with constant angular velocity to a rotation with varying angular velocity consists of chaindrive with an oval sprocket wheel. This mechanism is used for bicycles in order to pass quickly the pedal positions, which give a bad moment of the pedalcrank. It has the disadvantage that you can neither adjust the amplitude, nor the phase of the angular velocity.